ERA20LA023

Before departing on a local flight, the pilot idled the airplane for about 5 minutes to let the engine warm up. During the takeoff, about 40 feet above ground level, the airplane "seemed to quit climbing" and the engine rpm was decreasing. He pushed the throttle full forward, verified the carburetor heat was off, and the fuel shutoff valve was on. Realizing that the airplane would not clear trees and powerlines ahead, he aborted the takeoff and the airplane touched down about 100 ft before the end of the runway. The airplane continued off the runway and through a wooden fence. Postaccident examination of the engine revealed no evidence of preimpact mechanical malfunctions or failures that would have precluded normal operation. The weather conditions at the time of the accident were conducive to the formation of serious carburetor icing at glide (idle) power settings. Thus, it is likely that during the ground delay, a period during which the engine would typically be operating at low power, carburetor ice formed, and subsequently resulted in a loss of engine power during the initial climb. Had the pilot used carburetor heat before the takeoff, he might have eliminated the ice.

On October 27, 2019, about 1600 central daylight time, a Piper J3C-65, N7009H, was substantially damaged when it was involved in an accident near Grand Bay, Alabama. The airline transport pilot and passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot stated that a preflight inspection and engine run-up revealed no anomalies; he checked the carburetor heat and the engine power decreased 50 rpm. Because of the short taxi time, he allowed the engine to warm up for about 5 minutes before initiating takeoff. When the airplane was about 40 ft above ground level, it "seemed to quit climbing" and the engine rpm was decreasing. He pushed the throttle full forward, verified the carburetor heat was off and the fuel shutoff valve was on. He added that the engine was not running rough and was not spitting and sputtering. When he realized that the airplane would be unable to clear trees and powerlines ahead, he aborted the takeoff and slipped the airplane to lose altitude. He touched down about 100 ft before the end of the runway and was unable to stop the airplane before going off the end. The airplane continued through a wooden fence and came to rest on the other side of the fence. Postaccident examination of the engine was performed by a Federal Aviation Administration airworthiness inspector. Impact damage to the induction manifold assembly, propeller, and both main landing gear precluded an operational test of the engine. Although the inspector had limited tools available to perform the examination and the resting position of the engine precluded 360° rotation of the propeller, the inspector reported no discrepancies with the valve train, air induction, exhaust, and fuel supply system components. The carburetor heat cable was intact and connected, but could not be operationally tested due to impact damage. The engine oil was approximately 4 quarts (normal capacity). The inspector did not remove the spark plugs, check the timing of the magnetos, or check their functionality. A sufficient quantity of fuel was noted in the fuel tank and a check of the fuel strainer revealed no contaminants. At 1556, the weather reported at Mobile Regional Airport Field (MOB), about 10 miles northeast of the accident site, included a temperature of 22°C (72°F) and a dewpoint of 13°C (55°F). The calculated relative humidity at this temperature and dewpoint was about 58 percent. Review of the icing probability chart contained within Federal Aviation Administration Special Airworthiness Information Bulletin CE-09-35 revealed the atmospheric conditions at the time of the accident were "conducive to serious icing at glide [idle] power."